1. Field of the Invention
The invention relates to a vehicle equipped with a plurality of gas tanks that are different in heat dissipation characteristic.
2. Description of the Related Art
An example of vehicles as mentioned above is known as a fuel cell vehicle into which hydrogen gas is filled from a hydrogen station (see Japanese Patent Application Publication No. 2005-155869 (JP-A-2005-155869)). In Japanese Patent Application Publication No. 2005-155869 (JP-A-2005-155869), because the amount of internal temperature rise in the hydrogen tank when filling of hydrogen gas varies among various hydrogen tanks, filling the tanks with hydrogen is started with filling a certain amount of hydrogen gas only into a hydrogen tank whose heat dissipation characteristic is high. After that, filling the tank that has the high heat dissipation characteristic is temporarily suspended, and the filling a tank that has a low heat dissipation characteristic is started. After filling the tank that has the low heat dissipation characteristic ends, filling the tank that has the high heat dissipation characteristic is restarted to completely fill the tank that has the high heat dissipation characteristic. This series of filling controls is performed by switching a switch valve that is provided at a branching point of a filling passageway.
According to the filling method described in Japanese Patent Application Publication No. 2005-155869 (JP-A-2005-155869), it is possible to completely fill all of the plurality of hydrogen tanks that are different in heat dissipation characteristic. However, in this filling method, it is necessary to repeat relatively short-time filling processes, and therefore efficient filling process can not be performed.
In the case when the switch valve is omitted, the hydrogen tanks are simultaneously filled with hydrogen gas. However, the SoC (state of filling, that is, the percentage of filling) of a hydrogen tank reaches 100% (a completely filled state) more quickly the tank that has higher the heat dissipation characteristic. Therefore, if the filling control of the hydrogen tanks is performed in accordance with the SoC of the hydrogen tank that has the high heat dissipation characteristic, the hydrogen tank that has the low heat dissipation characteristic will not reach the completely filled state. On the other hand, if the filling control of the hydrogen tanks is performed in accordance with the SoC of the hydrogen tank that has the low heat dissipation characteristic, there is a risk of excessive filling of the hydrogen tank that has the high heat dissipation characteristic.